U.S. Pat. No. 1,666,257 issued Apr. 17, 1928 to Furnivall et al., teaches an exhaust silencer. The silencer is inserted into an exhaust pipe for engines and the like. The silencer comprises an inverted conical casing comprising a wire mesh placed in the exhaust pipe. The cone has a vertical circumferential wall defining a pipe extending above the base of the inverted cone and a screen mesh over the outlet of the pipe distant from the base of the cone. The cone and the pipe are filled with steel balls (e.g., ball bearings). The patent does not teach or suggest the embodiment of the present invention which has, along with other possible improvements over the state of the art, eliminated the essential inverted cone of the patent.
U.S. Pat. No. 2,545,682, issued Mar. 20, 1951 to Bergman, assigned to Universal Oil Products Company, teaches a silencer in an exhaust line above a pressure chamber such as a catalyst regenerator. The silencer comprises a cylinder having a conical top and bottom ends. At each end of the cylinder is a perforated plate or grating (Col. 3, lines 35 to 40). The column is packed with iron or ceramic balls. There are openings on the sides of the cylinder to add or remove balls. Additionally, the cylinder has valves to control the pressure within the cylinder. One embodiment of the present invention has, along with other possible improvements over the state of the art, eliminated the valves to control the pressure in the cylinder.
More recently, U.S. Pat. No. 6,343,672 issued Feb. 5, 2002 to Petela et al., assigned to NOVA Gas Transmission Limited, teaches a blow down and venting jet noise suppressor. The diffuser at the upper end of the device comprises an inverted truncated cone having a grid at each end. The inverted truncated cone is packed with spherical particles. One embodiment of the present invention has, along with other possible improvements over the state of the art, eliminated the essential inverted cone and the “swirler” below the inverted cone.
U.S. Pat. No. 7,451,855, issued Nov. 18, 2008 to Wang, teaches an acoustic absorbing device comprising a number of sound absorbing panels within a cylindrical hood. The sound absorbing panels have multiple perforations there through to help absorb sound. There is no particulate packing in the device. The patent teaches away from the many embodiments of the present invention.
In some embodiments, the present invention seeks to provide a simple effective means for suppression of noise from industrial exhausts or jets venting to the atmosphere.